Rotary cutters of the type used on roadway planers, also known as pavement profilers, road milling machines or cold planers, and on road reclaiming or scarifying machines, are well known in the art. An example of such rotary cutters is disclosed in British Patent Application No. 2,230,289A, published Oct. 17, 1990. The British publication discloses a rotary cutter having a plurality of cutting tools mounted in tool holders that are bolted to the flighting forming a spiral conveyor about the surface of a rotatable drum. The tool holders are secured to the flighting by screws that are threaded into threaded holes in the body of the tool holder. Other prior art arrangements secure the tool holders by screws, or bolts, threaded into holes provided in the drum surface or by welding the tool holder to the drum surface.
Tool holder mounting arrangements that require threaded holes in either the tool holder, drum surface or other fixture secured to the drum surface, are prone to thread damage. Overtightening of the screw member can strip the threads in the threaded hole. Impact forces acting on the cutting tool during operation of the rotary cutter can also damage the threaded connection. When such damage occurs, it is extremely difficult to remove the tool holder when replacement is required due to wear, breakage, or other damage. If threads disposed in the drum surface, or in a member permanently attached to the drum surface are damaged, the threads must be repaired by boring and cutting oversized threads or installing a threaded insert. Furthermore, the head end of the securing bolts or screws are often exposed to contact with the cut material, resulting in abrasive wear which further exacerbates the problem of removal and repair.
The present invention is directed to overcoming the problems set forth above. It is desirable to have a mounting arrangement for cutting tools on a rotary cutter wherein threaded holes are not required in either the tool holder or base member in which the tool holder is mounted. It is also desirable to have such as mounting arrangement in which the ends of the securing bolts are shielded from abrasive wear. Further, it is desirable to have a rotary cutter in which the tool holders are removably mounted in a recess provided in the radially outer surface of screw conveyor flighting comprising a plurality of replaceable segment members.